Support for metallic glow-filaments.



- candescent ANTON LEDERER,

OF ATZGEBSDOBF, NEAR VIENNA, AUSTRIA-HUNGARY. I

SUPPORT FOR METALLIC GLOW-FILAMENTS.

No Drawing.

, To all whom it may concern:

Be it known that I, ANTON LEDERER, a subject of the Empire ofAustria-Hungary, residing at No. 83, Atzgersdorf, near Vienna, in theProvince of Lower Austria, Austria- Hungary, have invented certain newand useful Improvements in Supports for Metallic Glow-Filaments, ofwhich the following is a specification.

My invention relates to im rovements in metallic supports for metal icglow filaments for electric incandescent lamps, and it has for itsobject to provide metallic supports of such a construction andcomposition that they will prevent bulging of the filament when thelatter expands in consequence of its being heated by the electriccurrent.

The necessity of supporting metallic glow filaments in electricincandescent lamps has been proved long since. Metallic filaments,however, do not allow the use of metallic supports, asis customary withelectric inlamps having carbon filaments. When supports of platinum orother bare (non-oxidized) metals are used, it has been observed that thefilaments may become fritted to the support. This fact is of nodisturbing influence with lamps that are continuously in use, that is tosay, that are not frequently cut out of circuit. However, if a lamp isrepeatedly and often cut in and'out of circuit, as is usually the case,it is observed that the filament surrounded and held by the supportvisibly bulges in the part of its length adjacent contact with thesupport. This bulging may cause short circuiting and other disagreeabledisturbances. This phenomenon may be explained as follows: When thefilament becomes fritted to the support and then strongly contractsafter having been cut out of circuit, there is formed at the place of'fritting a kind of angle or knot which prevents the free and unhinderedexpansion of the filament. With the successive operations of the lamp,new enlargements or knots are liable to be formed at other points alongthe length of filament so that the filament cannot readily slide throughthe support and it is thus caused to bulge outward.

This present invention has for its ob1ect Specification of LettersPatent.

to the point ofto prevent deformations of the glow filament such asthose above described, and still to allow the use of metallic supports,by coating the supports with an extremely thin layer of a compound ofthe metal used Eatented Nov. '7, 19.16; Application filed September18,1806. Serial No. 335,152. 1

for the support, preferably with an oxid of such metal. The layer ofoxid being extremely thin, the support formed according to the presentinvention retains its power of conducting heat, so that, on the onehand, no reduction of the oxid can take place and, on the other hand,the glow filament is prevented from fritting to the metallic support bythe protecting coating of oxid.

The supportingwire may be easily and conveniently provided with acoating of 02nd by passing it through an oxidizing flame. Nickel is anexcellent metal for use as the oxidized filament support, but I do notwish to be restricted to the use of nickel, since any metal which issufficiently refractory and which can be covered with a protectivecoating of one of its compounds is suitable for my use. I am aware thatfilamer t supports havev heretofore been made having filament-supportingloops or rings of refractory oxids attached to their ends. My filamentsupports are distinguished from these by the fact that my protectivecoatings are composed of compounds of the supporting metals themselves,and by the fact that the coatings do not extend beyond the ends of thesupports, and are thus interposed between the filaments and thesupporting wire. Since the filaments are separated from the metal wireonly by the thin coating, from the filament, and harmful localization ofheat is thereby avoided.

What I claim as my invention and desire to secure by Letters Patent is:

heat is quickly conducted away 1. In a metal filament incandescent lamp,1

v ment' and the mckel wire.

wire of highrefractability consisting of a, 5 nickel wire coated with"an oxid of nickel.

c 4.; A shield for the'support ofan incandescent metal bod consisting ofa coating of en oxid of the metal out of which said being thisinterposed. between the said fila- 3. As a support for incandescentmetal, a,

support is made, the said coating being thus interposed between theincandescent metal MD body and the metal of the support.

In witness whereof I haig e hereunto set my hand in presence of twowitnesses.

ANTON nnnnnnn Witnesses: JoHANN Lnson ALvnsTo S. Hoe'on.

